Linux 2.6.31-rc6
[linux-2.6] / arch / arm / mach-footbridge / dc21285-timer.c
1 /*
2  *  linux/arch/arm/mach-footbridge/dc21285-timer.c
3  *
4  *  Copyright (C) 1998 Russell King.
5  *  Copyright (C) 1998 Phil Blundell
6  */
7 #include <linux/init.h>
8 #include <linux/interrupt.h>
9 #include <linux/irq.h>
10 #include <linux/spinlock.h>
11
12 #include <asm/irq.h>
13
14 #include <asm/hardware/dec21285.h>
15 #include <asm/mach/time.h>
16
17 #include "common.h"
18
19 /*
20  * Footbridge timer 1 support.
21  */
22 static unsigned long timer1_latch;
23
24 static unsigned long timer1_gettimeoffset (void)
25 {
26         unsigned long value = timer1_latch - *CSR_TIMER1_VALUE;
27
28         return ((tick_nsec / 1000) * value) / timer1_latch;
29 }
30
31 static irqreturn_t
32 timer1_interrupt(int irq, void *dev_id)
33 {
34         *CSR_TIMER1_CLR = 0;
35
36         timer_tick();
37
38         return IRQ_HANDLED;
39 }
40
41 static struct irqaction footbridge_timer_irq = {
42         .name           = "Timer1 timer tick",
43         .handler        = timer1_interrupt,
44         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
45 };
46
47 /*
48  * Set up timer interrupt.
49  */
50 static void __init footbridge_timer_init(void)
51 {
52         timer1_latch = (mem_fclk_21285 + 8 * HZ) / (16 * HZ);
53
54         *CSR_TIMER1_CLR  = 0;
55         *CSR_TIMER1_LOAD = timer1_latch;
56         *CSR_TIMER1_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD | TIMER_CNTL_DIV16;
57
58         setup_irq(IRQ_TIMER1, &footbridge_timer_irq);
59
60         isa_rtc_init();
61 }
62
63 struct sys_timer footbridge_timer = {
64         .init           = footbridge_timer_init,
65         .offset         = timer1_gettimeoffset,
66 };